Motion-picture projector



Sept. 9, 1947. I R. J. MILLER I 7 2,427,296

MOTION I ICTURE PROJECTOR Original Filed May 1,1941 5 Sheets-Sheet 1 INVENT OR.

gegymobd'miiler Patented Sept. 9, 1947 UNITED STATES PATENT OFFICE MOTION-PICTURE PROJECTOR Original application May 1, 1941, Serial No. 391,258, now Patent No. 2,374,828, dated'May 1, 1945. Divided and this application July 29, 1944, Serial No. 547,164

12 Claims.

This invention relates to motion picture projectors and more particularly to an improved mounting for adjustably securing an aperture plate to a movable carrier arm.

In the operation of motion picture projectors, independent visual images carried by a strip of film of any suitable material are successively aligned with an aperture in a plate and are projected onto a screen by a light directed through the aperture and film.

Means such for example as an aperture pressure plate having a plurality of spaced film engaging members or shoes may be provided to yieldingly urge the film into engagement with spaced film tracks positioned adjacent the aperture.

It is desirable that the aperture pressure plate and film shoe guide plate be so mounted in a pressure plate housing that they can be separated from the aperture plate and film tracks to enable the operator to thread film into the projector. To facilitate manufacture of the projector and also to improve its operation by compensating for Wear, it is desirable that the film shoe guide plate and the pressure plat be vertically and horizontally adjustable relative to the aperture plate, film. tracks and the film driving means employed to intermittently align successive film frames with the aperture.

An object of this invention therefore resides in the provision of vertically and horizontally adjustable means to vary the position of the film shoe guide and pressure plates relative to the film tracks and the intermittently driven sprocket employed to align successive film frames with the aperture.

Still a further object of the invention is to provide readily accessible manually operable means whereby the pressure plate and its associated housing may be removed from its carrier for cleaning, inspection or repair without disturbing the adjustment of the film shoe guide plate relative to the film guiding and driving means.

Another object is to provide vertically and horizontally adjustable mounting means for detachabl connecting a pressure plate housing to a carrier arm in such a manner that the position of film guide shoes relative to film tracks can be varied, and the contact position of a film guide shoe relative to an intermittently driven sprocket may be readily adjusted.

Another object is to provide a projector having simplified and rugged film guiding means which may be economically manufactured.

Other objects and advantages of this invention will be apparent from the following detailed description considered in connection with the accompanying drawings, submitted for purposes of illustration only, and not intended to define the scope of the invention, reference being had for that purpose to the subjoined claims.

In the drawings wherein similar reference characters refer to similar parts throughout the several views:

Fig. 1 is a perspective view of a motion picture projector embodying the present invention.

Fig. 2 is a longitudinal sectional view of the projector through the aperture pressure plate.

Fig. 3 is a sectional .view taken substantially on the line 33 of Fig. 2 looking in the direction of the arrows.

Fig, 4 is a fragmentary elevational view of the bracket illustrated in Fig. 3 for adjustably attaching the pressure plate housing to a carrier arm.

Fig. 5 is a fragmentary sectional view of a modified form of attaching bracket.

Fig. 6 is a sectional view taken substantially on the line 6-6 of Fig. 5 looking in the direction of the arrows.

Fig. '7 is a top plan view of the attaching bracket illustrated in Figs. 5 and 6.

Before explaining in detail the present invention it is to be understoodthat the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it isto be understood that the phraseology or terminology employed herein is fo the purose of description and not of limitation.

Referring now to the drawings, it will be observed that the invention is illustrated as being embodied in a motion picture projector having a main casing l2. The space within the casing I2 is preferably divided by a substantially vertically extending intermediate wall l4 into a film compartment 1 6 and a mechanism compartment.

Upper and lower film driving sprockets l8 and 253 and an intermittently driven sprocket 22 project through the intermediate wall [4 and are provided with radially extending sprocket teeth 24 adapted to engage within spaced apertures in film 25 to drive it. The sprockets I8 and 20 are driven by suitable gearing in the mechanism compartment to move the film at a substantially predetermined speed. The intermittently driven sprocket 22 is driven from the mechanism compartment by a suitable intermittence driving mechanism to momentarily align successive film frames with an aperture 28 formed in an aperture plate 30 carried by an aperture plate housing 32.

The aperture plate 30 is preferably supported between film tracks 34 and film track carrier 32 aligned with the aperture plate housing 32 and with a wall 38 extending transversely from the intermediate wall I4 and spaced forwardly from a back wall 40 of the main casing I2.

The film 26 is drawn into the film compartment I6 through a slot 42 formed in the upper wall of the casing I2 by the upper film driving sprocket I8. After leaving the sprocket I the film is directed over the top of a shoe guide plate 44 between film guide rollers 46 and 48 mounted on a shaft 50 carried by bosses 52 and 54 associated with the aperture plate housing 32. The film '26 is then intermittently moved downwardly by the intermittently driven sprocket 22 to momentarily align successive film frames with the aperture 28.

The film 26 is maintained in contact with the sprocket teeth 24 of the intermittently driven sprocket 22 by a film tension shoe 56 which comprises an intermittence sprocket shoe 58 so pro- 'portioned as to follow the general contour of the intermittently driven sprocket 22 and maintain the film in engagement with the sprocket teeth 24.

Means such for example as a spring 60 may be provided to yieldingly urge the intermittence sprocket shoe 58 towards the intermittently driven sprocket 22 to exert sufiicient pressure on the film 26 to prevent disengagement or the film from the sprocket teeth 24. The spring 50 may be adjustably mounted on a screw 62 threaded into the film shoe guide plate 44 whereby the pressure exerted on the film by the intermittence sprocket shoe 58 can be varied to maintain the film under a desired tension. A stripper plate 64 may be provided to prevent the film 26 from winding up on the sprocket 22 in the event of film breakage.

After leaving the sprocket 22 the film preferably forms a backwardly directed loop extending into an outwardly flared portion 66 of the back wall 40. The film is then directed over the lower film driving sprocket 20 and is discharged from the film compartment I6 th'rough an opening 68 preferably communicating with a sound head.

Projecting light is directed towards the aperture 28 from a suitable light source preferably positioned behind the projector. A shutter of any suitable form such for example as a rotatable member having angularly inclined blades I2 may be provided to intermittently interrupt the fiow of projecting light into the film compartment I6 to prevent streaking as successive frames of the film 26 are moved into alignment with the aperture 28 and to prevent visible flicker.

The shoe guide plate 44 is mounted in a pressure plate housing I02 mounted on a carrier arm I04. The carrier arm I04 is slidably mounted on a plurality of vertically spaced generally horizontal disposed rods I06 extending longitudinally in the film compartment I6 and attached to the intermediate wall I4.

Motion transmitting means controlled by a lever I08 positioned between the housing I02 and a fixed portion of the projector may be provided to move the pressure plate housing I02 and the pressure shoe guide plate 44 away from the aperture plate 30 and film tracks 34 to enable the operator to thread film into the projector. A telescoping light shield in the form of a ring I09 mounted on studs III carried by the housing I 02 may be yieldingly urged by springs II3 towards a. lens tube II5 to enable the housing I02 to separate from the aperture plate to permit the operator to thread film into the projector and to facilitate removal of the pressure plate housing from the film compartment. The lens tube H5 is supported on a plurality of the vertically spaced horizontally extending rods I06 by a lens tube carrier arm I IT.

A knob IIO carried by a locking shaft II2 may be provided to project through the pressure plate housing I02 to enable the operator to readily remove the pressure plate housing I02 and shoe guide and pressure plates from the carrier arm I04 to clean or adjust them.

A plurality of vertically spaced relatively small film engaging shoes I I4 and I I6 may be provided to yieldingly urge the film 26 into engagement with the film tracks 34 to maintain the film in a substantially predetermined spaced relation relative to the aperture 28. The film engaging shoes II4 and H6 project through slots H8 and I20 formed in the shoe guide plate 44 and are provided with laterally extending projections I22 which prevent the shoes from passing complete- 1y through the slots II8 and I20.

Means may be provided to vary the pressure exerted on tho film by each of the film engaging shoes. One illustrative example of a mechanism for varying the pressure exerted by spaced shoes comprises a pressure plate I28 fioatingly mounted relative to the shoe guide plate 44 and having independent vertically spaced springs such as those illustrated at I24 and I26 interposed between the pressure plate I28 and each of the film engaging shoes II 4 and H6. The springs I 24 and I26 may be operably connected to the pressure plate I28 by suitable screws I30. The pressure plate I23 is thus resiliently mounted on the shoe guide plate 44 and is guided by screws I32 in such a manner that the pressure plate can vary its position angularly to equalize the pressure exerted by the springs on each side of the shoe guide plate 44.

Means may be provided t independently vary the pressure exerted on the film by the vertically spaced film engaging shoe II4 and H6. One desirable form of such pressure varying means comprises cam members I 34 and I36 carried by vertically spaced shafts I38 and I40 journalled in the pressure plate housing I02 and engaging vertically spaced cam followers I42 and I44 carried by the pressure plate I28. The shafts I38 and I 40' project beyond the outer edge of the pressure plat housing I02 and are provided with knobs I43 and I48 whereby they may be independently rotated to vary the pressure exerted by the vertically spaced shoes II4 and H6. The shafts I38 and I40 may be formed with serrated end portions I50 adapted to be engaged by a spring pressed locking clip I52 to prevent the shafts from rotating to vary the pressure exerted on the shoes until subjected to a substantially predetermined manual rotating force.

Attention is called to the fact that the unsprung Weight of the film engaging shoes II4 and H6 is minimized because a relatively large number of relatively small and light shoes are employed. Each of the shoes is yieldingly urged towards the film tracks 34 by its individual spring so that any disturbance caused by the film is not transmitted to the next shoe. Such disturbance of the film may be caused by a variation in thickness of film or by the presence of a splice in the film-where two pieces of film have been joined together. When this splice passes through between the film engaging'shoes and the film tracks it is necessary for'the shoes to mov away from the tracks to allow the splice to pass. Thus it will be seen that if the unsprung weight of the film engaging shoes is low they will recover their original position more rapidly than if the unsprung weight of the shoes were high. Also, it will allow the patch to pass through with less resistance since the inertia is low. It will be noted that only one pair of shoes is effected at a time by the patch while the remaining shoes are performing their function uninterrupted. This all goes toproduce a steadier alignment of the film resulting in a minimum disturbance of the picture on the screen.

It will be noted that it is possible to vary the pressure exerted on the film by th upper and lower film engaging shoe H4 and H6 respectively. For example, the lower shoes I16 positioned closer to the intermittently driven sprocket 22 may be adjusted to exert greater pressure on the film 26 than the upper film engaging shoes II4 to give more stabilizedcontrol of the film.

Means ma be provided to mount the pressure plate housing I02 on the housing carrier arm I04 in such a manner that it may be adjusted vertically andhorizontally to properly align'it with the aperture plate housing 32.

One desirable form of such adjustable mounting means comprises an adjustable locking device more clearly shown in Figs. 3 and e. The arrangement of the parts is such as to permit ready removal of the pressure plate housing I02 as a unit from the film compartment 16 of the projector,

The carrier arm I04; is provided with a plate I90 having a laterally extending pin Hi2 projecting therefrom. 'The plate I90 may be secured to the arm I04 by a plurality of screws I94 projecting through generally arcuate shaped slots in the plate I90 whereby the plate may be rotated slightly relative tothe arm I04 to adjust 'the vertical position of'the pressure plate housing I02 relative to the aperture plate housing 32,

A male cone I96 maybe secured to the plate 190 by a plurality of screws I98projecting through vertically extending slots in a fiange 200 carried by the male cone I96 whereby the cone-.canr'be elevated or lowered slightly relative to the plate I90 to adjust the contact position of the intermittence sprocket shoe 58-relative to the intermittently driven sprocket 22.

The pressure plate housing I02 is provided-with a laterally extending female cone 202 adapted to receive the male cone I96 and is also provided with an apertured boss 204 adapted to receive the pin I92.

The pressure plate housing I02 may be locked and unlocked in position on the -male cone I96 by a locking key 206 carried by the locking shaft I I2 and adapted to project inside the male cone I96 through a slot 208. The locking key 206 is actuated by the locking shaft I I2 having the actuating knob I I0 and is maintained in looking position by the tensionof a spring 2I0.

Frequent removal of the pressure plate housing I02 is desirable in order to permit cleaning of the pressure plate; housing and the film tracks and shoes. The removal of the aperture pressure plate housing as a unit is accomplished by turning the locking key 206 from the vertical position to the horizontal position so that it is aligned with the slot 208. In this position the locking key206 can bewithdrawn andrthe. entire pressure plate housing I02 may then be removed from the male cone In replacin the pressure plate housing, primaryadjustmentisobtained by the guide pin I92 carried :by the plate iI19Il entering the aperture of the boss 204.. Complete alignment is obtained by contact of the female cone '2 02 with the male cone I96. The actuating knob III!) of the locking shaft II2 having the locking key 206 is then pressed inwardly to compress the spring 2I0 until the locking key 206 projectsthrough the slot 208 and occupies aposition inside the male cone I96. The knob vI.I0:is thenrotated and the locking key 206 fits into shallow grooves on the inside of the male cone I96 as illustrated by the position occupied by the locking key 206 of Fig. 3. When the key 206 is moved t6 the locked position the knob I10 is-released whereupon the spring 2I0 holds the partssecurely in the assembled position because the pressure plate housin -I 02 is firmly supported and aligned at vertically spaced points on the cooperating cones =I96 and 202 and by the pin I92 and apertured boss 204.

Figs. 5 to '7 disclose a modified form of adjustable means for mounting the pressure plate housing I02- onthe vertically spaced horizontally extending rods I06-in the film compartment It.

A carrier arm 2I2 slidably mounted on a plurality of the vertically spaced rods I06 is provided with a threaded aperture 2I4 to receive a locking shaft 2'I6. A plate 2 I8 having an aperture 220 to receive the shaft 2 I5 in close contact therewith is interposed between the carrier arm 2I2 and a body section 222 of the pressure plate housing I02. The plate 2I8 is channel shaped and is provided with spaced flanges 224 positioned to engage the marginal edge portions 226 of thecarrier arm 2 I2 to maintain the pressure plate housing I02 in a predetermined, adjusted position relative to the film tracks 34 and the intermittently driven sprocket22.

Means may be provided to vary the vertical position of the pressure plate housing I02 relative to the carrier arm 21 2. One desirable form of means for. obtaining the desired vertical adjustment resides in the. provision of a bolt 228 projecting through a slot 2.30 formed in a generally horizontally extending flange 232 carried by. the plate 2 I 8. The bolt 228 is restrained from moving vertically relative tothe flange 23.2. by any desired means such. for example asspaced washers 234 and a pin 236 extending through the bolt 22.8. If the body section .222 of the housing I02. is made of relatively soft material-such for example as aluminum, a bushing :238 of a hard metal may be threaded into the body section 222 to receive the bolt 228 to prevent stripping threads in-the body section 222. The bolt 228 is manipulated to posh tion the pressure plate housing I02 in a desired verticalposition relative to the carrier arm 2I2 toad-just'the contact position ofthe intermittence sprocket shoe 58 relative to the intermittently driven sprocket 22.

Means. may be provided :to vary the vertical planeofe the pressure plate housing I02 relative to the carrier arm 2:I2 to align-the film shoe guide p1ate-44 with the film tracks 34. One desirable form of means for obtaining the desired vertical plane ad'j-ustmentiresides in. the provision of vertically spaced. bolts 240- projecting through slots 242 formed in theplate 2I8. The slots 242 may be arcuate shaped as illustrated to'permit varying the .ang'ularrelation ofthe pressure plate housing relative to the carrier arm to align the film shoes with the film tracks.

The slot 230 in the horizontally extending flange 232 of the plate 2E8 is of sufiicient length to permit movement of the body section 222 and screws 240 relative to the plate 218 as the housin I02 is adjusted vertically or angularly, and the slots 242 are of sufiicient width vertically to permit vertical movement of the body section on the bolt 228 to adjust the housing I 02 vertically to adjust the contact position of the intermittence sprocket shoe 58 relative to the intermittently driven sprocket 22. It will be noted that the housing I02 is thus mounted on the carrier arm 2 l 2 in such a manner that it can be moved vertically or angularly to bring the cooperating parts into a desired position of alignment and to compensate wear of the parts.

The locking shaft 2|6 projects through an enlarged bore 244 in the body section 222 whereby movement of the housing I02 vertically or angularly relative to the plate 218 and carrier arm 2| 2 is permitted to obtain the desired adjusted position. When the desired adjusted position has been obtained the locking screws 240 are tightened to lock the pressure plate housing I92 to the plate 2!!! thereby positioning the aperture 220 and plate H8 in a desired relationship with the body section 222.

This is a division of my c-pending application Serial No. 391,258, filed May 1, 1941, now Patent No. 2,374,828, issued May 1, 1945, which was a continuation in part of my earlier filed application Serial No. 250,310, filed January 11, 1939, now Patent No. 2,312,663, issued March 2, 1943.

I claim:

1. In a motion picture projector, an aperture plate, a movable carrier arm, a film shoe carrying member movable between positions adjacent and spaced from the aperture plate, connecting means between the carrier arm and film shoe carrying member comprising a plate maintained in substantially fixed horizontal and vertical positions relative to the carrier arm, and adjustable means between the plate and film shoe carrying member whereby the vertical position of the film shoe carrying member can be varied relative to the carrier arm and the angular position of the film shoe carrying member relative to the aperture plate can be varied.

2. In a motion picture projector having a film compartment, an aperture plate in the film compartment, a carrier arm in the film compartment, a shoe guide plate movable in the film compartment between an operating position adjacent the aperture plate and a threading position spaced from the aperture plate, a housing supporting the shoe guide plate, manually operable connecting means between the housing and carrier arm, and adjustable means between the manually operable means and the housing whereby the vertical and angular positions of the housing relative to the carrier arm can be varied.

3. In. a motion picture projector, an aperture plate, a pair of spaced film tracks associated with the aperture plate, means including an intermittently driven sprocket to momentarily align successive film frames with the aperture in the aperture plate, a film shoe carrying member movable between an operating position adjacent the film tracks and a threading position spaced from the film tracks, a housing supporting the film shoe carrying member, a movable carrier arm, connecting means between the housing and carrier arm comprising a locking shaft, an attaching plate having spaced flanges engaging the carrier arm and having an aperture to receive the locking shaft, and adjustable means between the housing and the attaching plate comprising vertically and horizontally extending bolts projecting through slots in the attaching plate and engaging the housing whereby the horizontal and vertical positions of the housing relative to the carrier arm and the contact position of the film shoe carrying member relative to the film tracks and intermittently driven sprocket can be adjusted.

4. In a motion picture projector, an aperture plate, a pressure plate housing movable between an operating position adjacent the aperture plate and a threading position spaced from the aperture plate, a movable carrier arm, connecting means between the pressure plate housing and the carrier arm comprising a locking shaft, and adjustable means between the locking shaft and the pressure plate housing whereby the vertical and angular positions of the housing relative to the carrier arm can be varied.

5. In a. motion picture projector, a plurality of horizontally extending rods, 2. pressure plate housing carrier arm slidably mounted on a plurality of said rods, a disk having a pin projecting therefrom adjustably mounted on the carrier arm, a male cone adjustably mounted on the disk, the male cone and pin being adapted to receive a female cone and an apertured boss of a pressure plate housing whereby the position of the housing may be adjusted vertically and horizontally.

6. In a motion picture projector having a film compartment including a fixed wall, a plurality of longitudinally extending rods mounted on the wall, an aperture plate in the film compartment, a pressure plate housing having a laterally extending female cone and an apertured boss, a pressure plate carrier arm slidably mounted on a plurality of said rods, a disk adjustably mounted on the carrier arm and having a pin projecting therefrom and adapted to engage the apertured boss, a male cone member adjustably mounted on said disk and adapted to receive the female cone of the pressure plate housing whereby the pressure plate housing may be vertically and horizontally adjusted relative to the aperture plate.

7. In a motion picture projector, an aperture plate, a carrier arm movable between positions adjacent and spaced from the aperture plate, a film shoe carrying member, a housing supporting the film shoe carrying member, connecting means between the housing and the carrier arm comprising vertically and angularly adjustable members interposed between the carrier arm and housing, and manually operable means to se cure the housing to the carrier arm in an adjusted position.

8. A motion picture projector comprising an aperture plate, a carrier arm movable between positions adjacent and spaced from the aperture plate, a film shoe carrying housing, connecting means between the housing and the carrier arm comprising vertically and angularly adjustable members interposed between the car rier arm and housing, and a single readily accessible member to secure the housing to the carrier arm in any adjusted position.

9. In a motion picture projector having a film compartment, an aperture plate in the film compartment, an intermittently driven sprocket to successively align spaced film frames with the aperture of the aperture plate, a film shoe pressure plate housing, a housing carrier arm movable between operating and threading positions adjacent and spaced from the aperture plate, an intermittence sprocket shoe carried by the film shoe pressure plate housing, and means to Vary the vertical and angular positions of the pressure plate housing relative to the carrier arm to adjust the vertical and angular contact positions of the intermittence sprocket shoe relative to the intermittently driven sprocket.

10. In a motion picture projector having a film compartment, an aperture plate in the film compartment, spaced film tracks associated with the aperture plate, a film shoe pressure plate housing, a housing carrier arm movable between operating and threading positions adjacent and spaced from the aperture plate, and means to vary the vertical plane of the pressure plate housing relative to the carrier arm to adjust the angular relation of the film shoe pressure plate housing relative to the film tracks.

11. In a motion picture projector having an aperture plate, spaced film tracks associated with the aperture plate, an intermittence sprocket to align spaced film frames with the aperture, a film shoe carrying member, an in-- termittence sprocket shoe, a housing supporting the film shoe carrying member and intermittence sprocket shoe, a housing carrier arm movable between operating and threading positions adjacent and spaced from the aperture plate, vertically adjustable means interposed between the housing and carrier arm to vary the adjusted position of the intermittence sprocket shoe relative to the intermittence sprocket, angularly adjustable means interposed between the housing and carrier arm to align the film shoe carrying member with the film tracks, and means projecting through said vertically and angularly adjustable means to secure the housing to the carrier arm in such a manner that it can be readily 10 removed and replaced without disturbing the vertically and angularly adjusted positions.

12. A motion picture projector comprising an aperture plate having spaced film tracks associated with the aperture plate, an intermittence sprocket to align spaced film frames with the aperture, a film shoe carrying member, an intermittence sprocket shoe, a housing supporting the film shoe carrying member and intermittence sprocket shoe, a housing carrier arm movable between operating and threading positions adjacent and spaced from the aperture plate, vertically adjustable means comprising a plate having a horizontal section interposed between the housing and carrier arm and a threaded member projecting through the horizontal section to vary the adjusted position of the intermittence sprocket shoe relative to the intermittence sprocket, angularly adjustable means interposed between the housing and carrier arm comprising vertically spaced threaded members projecting through openings in a vertical portion of said plate to align the film shoe carrying member with the film tracks, and means projecting through said plate to secure the housing to the carrier arm in such a manner that it can be readily removed and replaced without disturbing the vertically and angularly adjusted positions.

RAYMOND J MILLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,780,945 Sapier Nov. 11, 1930 1,830,158 Dina Nov. 3, 1931 2,192,641 Grifiin et a1. Mar. 5, 1940 2,211,827 Kindelmann Aug. 20, 1940 2,236,878 Kindelmann Apr. 1, 1941 2,140,738 Fitz Dec. 20, 1938 1,455,096 Roebuck May 15, 1923 

